1. Technical Field
The disclosure generally relates to a method for mixing light of LEDs and a lighting device using the method.
2. Description of Related Art
In recent years, due to excellent light quality and high luminous efficiency, light emitting diodes (LEDs) have increasingly been used as substitutes for incandescent bulbs, compact fluorescent lamps and fluorescent tubes as light sources of illumination devices.
Generally, a white light is provided by mixing light from a red light LED, a green light LED and a blue light LED. Since a peak wavelength of an LED will change according to a change of temperature, a temperature sensor is usually applied to the LED to monitor the change of temperature. When the temperature of the LED increases, an input current of the LED is decreased to avoid the temperature of the LED from continuously increasing. However, since the input current of the LED is decreased after the increasing of the temperature of the LED, there is a risk that the temperature of the LED has already been increased to an unacceptable value before the input current of the LED is decreased enough to bring the temperature down.
What is needed, therefore, is a method of mixing light of LEDs and a lighting device using the method to overcome the above described disadvantages.